不同分子质量牛骨胶原多肽制备复合膜特性研究

Microstructures and Properties of Bovine Bone Collagen Polypeptide Composite Films with Different Molecular Weight Distributions

作为畜禽屠宰业的副产物,动物骨含有蛋白质、脂肪等营养物质,合理利用动物骨可以减少环境污染与资源浪费。从骨骼中提取回收胶原蛋白/多肽、并加工为高附加值产品被认为是一个具有潜力的发展方向。然而,胶原多肽的分子质量及分布会影响其溶解度、粘度、胶凝能力和稳定性等理化性质,从而影响胶原多肽基复合材料的结构与性能。以不同分子质量的牛骨胶原多肽为研究对象,采用溶液流延法制备胶原多肽羧甲基纤维素复合膜,通过测定拉伸强度、断裂伸长率、水溶性指数、静态接触角等指标,考察复合膜的力学性能和疏水性,并结合傅里叶变换红外光谱分析、X射线衍射分析、热重分析和扫描电子显微镜等技术,探究胶原多肽分子质量对复合膜微结构与性能的影响及作用机理。研究结果表明:添加胶原多肽可以显著改善复合膜的力学性能和疏水性,且在肽分子质量为700~1000 u时复合膜性能最优,其表面结构致密,拉伸强度、断裂强度和杨氏模量较对照组分别提升2.39、2.55、10.11倍,断裂伸长率较对照组降低40%,疏水性和热稳定性也最理想;但随着牛骨胶原多肽分子质量的增加,复合膜的水溶性增加,力学性能和热稳定性显著降低。

As a by-product of animal slaughter,bone has high-quality protein content along with comprehensive nutrients.It will cause serious environmental issues and waste of resources if handled improperly.Collagen polypeptide(CP),prepared by enzymatic hydrolysis of animal bones,is respected in the fields of material applications,such as food,films,medicines,and composites,which is principally because such materials are considered to be promising solutions to environmental impacts of synthetic polymers.However,the molecular weight distributions of CP during the extractions of waste bone proteins may affect their physicochemical properties,mainly including solubility,viscosity,gelling ability and stability,thus significantly affecting the comprehensive performances of the composites.Therefore,it is of great significance to determine the optimal molecular weight of CP and explore its underlying mechanism of action in composites.The effects of molecular weight distributions of bovine bone CP on mechanical properties,water solubility,thermal stability,compatibility and microstructures of CP-carboxymethyl cellulose(CMC)composite films were investigated by using conventional methods,such as the Fourier transform infrared(FTIR)spectroscopy,X-ray diffractometry(XRD),and contact angle determination.A series of experimental composite films with a range of different molecular weight distributions of CP was fabricated by the film-casting method.The results showed that the addition of CP would significantly improve the mechanical properties and hydrophobicity of the composite films.The microstructures of the CP-CMC composite films were smooth and compact when the molecular weight distribution of CP was 700~1000 u.Meanwhile,the tensile strength,breaking strength and Young's modulus were about 2.39,2.55 and 10.11 times higher than those of the control group,respectively,while the elongation at break was 40%lower than that of control group,also,the hydrophobicity and thermal stability performed the best.With the increase of molecular weight distributions of CP,the water solubility of the CP-CMC composite films was increased,and the mechanical properties and thermal stability were reduced significantly,which may limit its industrial applications.The research results would provide a useful theoretical foundation and basic data to support the efficient utilization of animal bones and promote the transformation of CP into material utilization.